1. Field of the Invention
The present invention relates to a process procedure verifying system, and more specifically to a process procedure verifying system which is suitable for verifying the procedure of processes for manufacturing a semiconductor device, and which is intended to verify a prepared process procedure by using, as a knowledge base, data for process procedures being used, and by additionally considering the condition of a production line, when a product is manufactured by performing a plurality of predetermined processes in a predetermined sequence.
2. Description of Related Art
Now, a prior art process procedure verifying method will be described with reference to the flow chart of FIG. 1. In case of manufacturing a semiconductor device by carrying out a plurality of predetermined processes in accordance with a predetermined flow, a desired working process and a desired working condition are picked up from working processes and working conditions stored as data, and the picked-up working process and working condition are paired (step 101).
Then, the working processes each paired with the working condition, are arranged in a working sequence, to prepare a process procedure (step 102).
Next, the process procedure prepared in the above steps is checked (step 103). This checking is carried out by representing a surface condition (resist deposition, wafer exposure, etc.) of a wafer used for manufacturing the semiconductor device, by a plurality of different colors, and by observing the arrangement and the superposition of the colors in order to check whether or not there is a problem and to make modification if there is a problem (steps 103 and 104).
Thereafter, processing equipment used in the process procedure prepared in the above mentioned steps are counted, and a necessary equipment capability is calculated for each equipment group (step 105).
Then, the calculated result is added to the amount of use of a current production line (step 106), and whether or not the result of the addition exceeds the capability of the equipment is checked (step 107).
When the result of the checking in the step 107 indicates that there is a problem, a countermeasure such as an increase of the equipment capability and addition of the equipment is taken (step 108).
On the other hand, when the result of the checking in the step 107 indicates that there is no problem, or when the necessary countermeasure has been taken, the manufacturing is executed by using the obtained process procedure (step 109).
However, the above mentioned prior art process procedure verifying method includes a judgment by a human being, and therefore, it is a problem that the degree of precision in the judgment depends upon experience and perception of a skilled person.
Therefore, it is not easy to increase the number of operators capable of performing this process procedure verification, and accordingly, this verification work is loaded onto limited persons (skilled persons), with the result that a long time is required to complete the work, and it becomes an obstruction in elevating work efficiency. Therefore, a problem occurs in which a start of various experiments and manufacturing in order to produce a new product is delayed.
In addition, the above problem has become more serious because of the inclination of a many-kind, few-production in the semiconductor device.
Another problem is that because the experiments rely on the perception of a human being, the result is different from one operator to another and therefore never becomes constant. A further problem that there is possibility that because of a human-caused error, such as a misjudgment which is unavoidable because of a human's work, a product is produced with a problem existing in the process procedure.
In this case, since the semiconductor device is produced in a job-shop flow, when a product concerning a problematic process procedure is processed in an equipment and the equipment is contaminated as a result, if the contamination remains undiscovered and another product is processed in the contaminated equipment, the another product is also contaminated and therefore becomes defective. As such, there is a problem that not only the first product itself, but also subsequent products are adversely influenced.
On the other hand, when a process procedure for a new product is prepared, there is an inclination that a designer adds many measuring steps and inspecting steps, from the viewpoint of taking safety of the product into consideration to the utmost, and limits the working equipment in order to cause the work to be carried out in an equipment having a good performance.
In the above mentioned case, since no trouble occurs in the process procedure, the prepared process procedure will pass, with no problem, the checking by a person who checks the process procedure. Therefore, when the necessary equipment capability is calculated, the work is concentrated to limited equipment, with the result that there occurs such a problem that the working period for manufacturing the product becomes long and the equipment investment increases.
In connection with this kind of technology as mentioned above, for example, Japanese Patent Application Pre-examination Publication No.
JP-A-02-162463 proposes a system for supporting a preparation of a process network for representing the procedure of works and actions, and Japanese Patent Application Pre-examination Publication No. JP-A-02-130678 proposes a manufacturing plan preparing system for automatically preparing the execution sequence of jobs in order to elevate the production efficiency.
In brief, JP-A-02-162463 proposes a process network preparation supporting system of replacing the processes by networks and preparing the process procedure having no contradiction. This process network preparation supporting system is surely effective in the job-flow type manufacturing process, typified by an assembling operation, but has not yet solved the above mentioned problems in the job-shop type manufacturing process such as semiconductor device manufacturing, since the same product is processed many times in the same equipment.
On the other hand, JP-A-02-130678 proposes a method for efficiently executing the manufacturing work by using a simulation technology in the manufacturing plan preparing system for automatically preparing the execution sequence of jobs in order to elevate the production efficiency. This method makes it possible only to cope with the concentration of products to be processed, by efficiently utilizing the capability of the equipment. However, the problems has not yet been solved.